Since a fine and precise surface is required for a substrate that is used for a semiconductor device or a display device requiring a high degree of integration, various planarization methods are applied. Particularly, due to the trend of high integration and high performance of the semiconductor device or display device, a polishing method of relatively moving a polishing pad and a subject to be polished, while supplying a slurry composition including polishing particles and various chemical ingredients between the polishing pad and the subject to be polished, is generally used. In this polishing method, for more precise polishing, the subject to be polished is fixed on a mounting pad so as to maintain a constant location and position during the polishing or processing process.
Meanwhile, Japanese Patent Publication No. 2006-334745 discloses a polyurethane foam prepared by reacting and curing polyols, polyisocyanates, a foaming agent, a catalyst, and a water repellent, and a polishing pad obtained using the same. However, since this polyurethane foam is obtained by using a foaming agent such as water, methylene chloride, or carbon dioxide gas, it has a relatively high hardness or it is difficult to form uniform distribution of long and large internal pores, and to obtain high compressibility and compression recovery rate in the range of low hardness.
The previously known mounting pad has internal pores of different sizes and the distribution of the pores is irregular, and thus the cushion property and adsorption to a subject to be polished are poor. Further, a subject to be polished cannot securely contact the mounting pad during a polishing process, and thus precise polishing may not be achieved. In addition, since the previous mounting pad exhibits non-uniform size and distribution of internal pores, the physical properties such as compressibility and compression recovery rate are poor and water repellency is not sufficient, and thus a subject to be polished does not have uniform contact during a polishing or processing process.
Accordingly, there is a need to develop a novel mounting pad for more precise and efficient polishing of the substrate that is used in a semiconductor device or a display device.